The Allen Telescope
Array is a joint effort between the
SETI Institute and
the Radio Astronomy Laboratory of the University of
California, Berkeley, and is being constructed at
Berkeley's Hat Creek Observatory in the Cascade Range of
northern California. This rural site has a low
population density, ensuring a radio quiet environment.

The
Allen Telescope Array will be an
astronomical instrument unlike any
other. First and foremost, it is the
only major radio telescope purposely
built for the "Search for
Extraterrestrial Intelligence" (SETI). It
is a telescope of unusual design,
constructed from a very large number of
relatively small antennas. Forming a
large radio "mirror" in this way has
long been recognized as a technically
sound idea, but - until now - an
impractical one for an array of such
capability. The cost of electronically
connecting hundreds of antennas together
was prohibitively high. However, thanks
to the rapid pace of the digital
revolution, what was once impossible is
now both feasible and attractive. The
Allen Telescope Array will cost only
about one-fifth as much as conventional
radio telescopes of similar collecting
area. And because it is an array, rather
than a single dish, it can rapidly make
detailed radio "photographs" of the
cosmos.